46 PLANT BREEDING. 



Harvesting and selecting the nursery-grown wheat is almost entirely 

 a matter of elimination. A careful man removes from the plot about 

 95 per cent of the plants, leaving tlie comparatively few strongest 

 and most desirable plants. In Plate III, figure 1, are shown two plots 

 which contained 100 plants each From the one on the right 90 have 

 been removed, leaving the 10 best standing. The spikes are cut from 

 each plant separately and preserved in a packet or envelope. Where 

 desii-ed, the straw from each plant also may be harvested separateh^ 

 and placed in an envelope by itself; or, if thoroughly dry, it can be 

 Aveiglied at once. Where the variety has too weak straw, causing the 

 crop to lodge, or where the straw is of little value as compared with 

 the grain, the height, the weight, and the ability of the straw of each 

 plant to stand erect are desired, that plants may be chosen which will 

 increase the proportion of grain to straw. 



When dry the contents of the packets are weiglied. All the plants 

 which are low in weight are at once discarded, even Ijefore shelling, 

 reducing the labor of shelling to the few best. The shelled grain 

 having been weighed to get the net weight, the grade or quality deter- 

 mined, and any other notes of interest made, the breeder is in position 

 to make choice of the best plants. One hundred, more or less, of the 

 seeds from each of these few chosen plants are planted in separate 

 nursery plots in the wheat-breeding nursery the second season in a 

 manner similar to that under which the seed was grown the first 

 season. These collections of plants are called "centgeners," this 

 word having been originated to mean a hundred j)lants, more or less, 

 springing from the seeds of a single mother plant — that is, a large 

 number of one generation. Each group of plants from a single mother 

 plant thus planted in a centgener plat is given a nursery-stock num- 

 ber, written thus: "Nursery stock No. 17, 1892," this serving as a 

 name for this stock so long as it is in the nursery. In case any stock 

 becomes especially prominent in the wheat nursery, all or part of its 

 seed is transferred to the field trials, w^here it is given a Minnesota 

 number, as "Minnesota, No. 168, wheat." The nursery stock num- 

 ber, the class name of the parent wheat, also its Minnesota number, 

 and any facts regarding its historj^ are entered upon a blank card, 

 called "Introductory Sheet," w^hich is placed as the first card in the 

 history of the nursery wheats. The form of this sheet is as follows : 



SELECTED STOCK— INTRODUCTORY SHEET. 

 (Minn. Form 61.) 



Wheat: Class name of parent stock, . Nursery stock No., . Minn. No. of parent 



stock, . 



Date, , . 



Origin and history of parent stock: 



Size, oi by Si inches; color of card, white. 



